Remote control system for radio receiving apparatus and the like



April 24, 1934.

A Q R. GARRETI' xmms common ssm roxmto nscsxvnw un ma Lm:

Filed Sept. 8, 1930" 2 Sheets-Sheet 1 7 Inventor- Char-lcs R.Gar-1ett.

His Attorney.

April 24, 1934. Q R' @ARRET-'r 1,956,419

REloTE coN'rEoL sYstEl FOR RADIO RECEIVING APrARA'l-us m THE LIKE film: sagt. 8, .1930 2 sheets-sheet 2 77 Inventor'.

Chomles RGmvett, bg MM ZAM His Atto-#neg Patented Apr. 24, 1934 PATENT OFFICE REMOTE CONTROL SYSTEM FOR RADIO RECEIVING APPARATUS AND THE LIKE Charles R. Garrett, Westmont, N. J., assignor to General Electric Company, a

New York corporation of Application September 8, 1930, Serial No. 480,464

4 Claims.

The present invention relates to a remote control system for `radio receiving apparatus and the like, and more particularly it relates to an automatic electrical remote control system for the remote tuning of radio receiving apparatus and the like to preselected signal channels or stations.

For preselected channel operation, the control or station selector of the apparatus is arranged, upon operation of a selector device, to be moved to and stopped at any selected one of a plurality of preselected settings or positions of adjustment, corresponding to any one of a plurality of preselected transmission channels or stations which it is desired to receive regularly.

In applying a remote control means to an apparatus, such as a tuned radio receiving apparatus, requiring extremely fine and accurate adjustment, simple, dependable and consistently accurate control devices and circuits are required and the inherently undesirable operating characteristics of relays, multiple contact switches and the like must be avoided. In tuning, as is well known, accuracyof adjustment is of primary importance and involves a control which is adjustable to a small fraction of a degree or of an inch to obtain a desired setting of the tuning control device, and in carrying out automatic preselected channel tuning the control means must be capable automatically of repeatedly adjusting the tuning means of the apparatus exactly to any preselected position or setting each with the same extreme accuracy as vobtained by direct manual adjustment of the tuning device itself.

It is therefore a primary object of the present invention to provide an improved and simplified,

electrical remote control system for moving a controlling member such as a tuning control shaft, of an apparatus such as a radio receiver within a certain range of movement of said member, such as a normal operating control or tuning range, or to any one of a plurality of preselected positions within said range, in response to the operation of a remotely located selector and control means arranged to designate any one of said preselected positions, without utilizing complicated circuits, multicontact switching means or relays.

It is a further object of the present invention to provide an automatic electrical remote control means of the above character which is adapted to be applied to a radio tuning control means and automatically upon remote control designation, to move said tuning control means from any position of rest or motion in the direction of and to stop it exactly in any designated and predetermined one of a plurality of predetermined positions corresponding to any one of a plurality of desired and preselected signal channels or stations to which the apparatus is responsive.

It is a still further object of the present invention to provide an electrical remote control means for radio receiving apparatus and the like, which is adapted for automatic control operation of the above character under the control of a timing device, such as a clock mechanism, whereby the apparatus may successively be adjusted for any one of a series oi' selected operating conditions or be tuned successively to each one of a series of preselected channels or stations, each during a definite and preselected time interval, all with the same consistent accuracy.

The invention will however better be understood from the following description when taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

In the drawings Fig. 1 is a diagrammatic view in perspective of an electrical remote control means embodying the invention and applied to the tuning control of a radio apparatus; Fig. 2 is a detailed view in elevation and partly in crosssection on an enlarged scale, of a portion of a selector mechanism employed in connection with Fig. 1; Fig. 3 is a further diagrammatic view in perspective of a portion of the apparatus of Fig. 1 showing a modification of a switching means, and Fig. 4 is a schematic wiring diagram showing a lmodification of a remote control unit adapted for push kbutton operation and time control.

Referring to Fig. 1, 5 is a multiple unit condenser providing a variable tuning control means for a radio receiving apparatus, the remainder of which is not shown for the reason that it does not concern the present invention. The tuning range is covered by substantially 180 degrees of rotation of the tuning controlling element or condenser 5 of the present example. The condenser is provided with a rotatable control shaft 6 which is connected with a driving motor 'l through a reduction gearing including a worm gear 8 mounted on and secured to the motor shaft 9 and a worm wheel 10 mounted on and secured to the tuning control shaft 6. 'Ihe motor operates to drive the tuning control shaft in either direction and the gearing provides a single reduction of relatively high ratio whereby the tuning control shaft is operated at a. slow rate, and furthermore provides a friction load or damping effect upon the motor to prevent any tendency to hunt in operation.

The motor is preferably of the alternatingcurrent shifting-field type having a pair of parallel connected energizing or operating windings 11 provided with connection leads 12, and reversing or control windings arranged as pole shading windings, in two-series-connected groups 13 andv 14 for four poles. Groups 13 and 14 are connected in series as indicated and have a common connection or lead 15 between them, and two terminal leads 16 and 17 providing reversing leads.

Power such as commercial alternating current, is supplied from a suitable source, such as mains 18, to windings 11 of the motor to energize the latter, through leads 12 and a stepdown transformer 19 connected with said power supply source. A pair of leads 21 and 22 are connected between the transformer and the motor to provide a switch circuit which may be closed and opened to energize and deenergize the motor. For connection to a remote control unit, hereinafter described, by a cable wire connection, leads 2l and 22 are provided with terminals 23 and 24 respectively, on a suitable terminal board 25 associated with the apparatus.

Jointly supplied from the same power source, is transformer 26 which for this purpose is connected in parallel with transformer 19. As indicated, the transformer 26 is intended to supply the apparatus associated with the tuning control means with power and the common supply leads for this transformer and transformer 19 are arranged to be energized through a common primary or power switch circuit 20 provided with cable connection to terminals 27 on board 25. In order to energize the transformers 19 and 26, it is obvious that circuit 20 must be closed, and that to operate the motor, circuit 21-22 must also be closed. The means for closing and opening these circuits will hereinafter be described.

With the vmotor energized, it is operated by connecting either reversing lead 16 or 17 to the common return lead 15. This short-circuits one or the other of the sets of control or reversing windings 13 and 14, and causes the motor to operate in one direction or the other depending upon which lead is connected with lead 15. In the present example, the arrangement is such that when lead 16 is connected with lead 15 the motor will operate to drive the tuning control shaft in a counter-clockwise direction as viewed in the drawings, while when lead 17 is connected with lead 15 the motor will operate to drive the tuning control shaft in a clockwise direction.

' With leads 16 and 17 disconnected from the leads 15, the motor will stop or remain at rest.

For connecting and disconnecting the above leads in the proper manner for stopping the motor and for operating it in either direction, that is, in a forward and a reverse direction, the reversing and the control circuit of the motor, through reversing leads 16 and 17 and the common return lead 15, is completed through any one of a plurality of reversing and stop switches 30-37 inclusive, and a selector switch means 38 connected in series therewith. The reversing and stop switches are single-pole double-throw switches having operating contacts 28 and 29 in each of which the switching means in the form of a exible arm is movable to close in opposite directions from a neutral or central' open position. One each of said switches is provided for each preselected position which it is desired that the controlling device of the controlled apparatus tor is conducted up to the reversing and stop switches directly by the reversing leads 16 and 17, as indicated. The former lead is connected with one set of contacts 28, one for each switch, and the latter lead is connected with the other set of contacts 29, one for each switch, whereby corresponding contacts in the series of switches are connected in parallel as indicated.

A control or selector lead 39, also, in the reversing and control circuit for the motor, provides a circuit connection from each switch with a corresponding individual switch contact 40 in the selector switching means 38. To provide this connection, the leads 39 are connected with suitable terminals 41 on the terminal board 25 for a, cable 42 in which they are conducted to the selector switching means 38. The cable connection is provided as a convenient means for extending the control circuits to any suitable remote control location for the selector means 38 and in the present example, as a mounting means for the selector means 38 and other controls, a panel or mounting board 43 is provided.

.Leads 21 and 22 for the motor switching circuit for energizing and deenergizing the motor are also extended through the cable 42 from the terminals 23 and 24 to the selector switching means 38, lead 22 being connected jointly with a movable contact arm 44, associated and movable to connect individually with contacts 40, and with a movable contact 45 associated with a fixed contact 46, with which last named contact, lead 2l is connected. Leads 21 and 22 may then be connected to energize the motor, by closing the contact 45 with the contact 46. The switch contacts are normally biased to the open position by any suitable means such as a spring 47.

It will be` noted that the lead 22 is ccnnected at 48 with the lead 15 of the reversing and control circuit for the motor, hereinbefore described, whereby lead 22 not only provides a motor energizing or switching lead fer the motor energizing contact 45, but also a circuit return lead from selector switching means 38 to lead 15 for the reversing and control circuit of the motor, from the contact arm 44 cf the selector switching means 3B. This dual connection for lead 22 permits a reduction in the number of leads required in the cable 42.

For convenience in operation of the apparatus, the remote control panel 43 may be provided with a primary or power switch 49 for the apparatus, connected through the cable 42 with switch leads 20 and terminals 27, and a suitable volume control device such as a potentiometer 50 having a volume control circuit connection with the apparatus, through the cable 42 in suitable leads 51 provided with terminal board connections as indicated at 51. It should be noted that in the diagram of Fig. 1, the various leads enter and leave the cable in the same order from right to left and vice versa, so that the various circuits may easily be traced.

With the above described reversing and control arrangement, it will be seen that the reversing and stop switches 30-3'7 inclusive selectively through leads 16 and 17, may connect either side of the motor reversing circuit with selector leads 39 and individual selector' contacts 40 in the remotely located selector switch means 38. By` closing return lead 22 with any one of the selector contacts 40 by adiustment of selector arm 44, the motor reversing and control circuit may be completed through any selected reversing and stop switch to the common or return lead 15. With the contacts and 46 closed and the motor energized, the motor will then remain at rest or will operate in one direction or the other as determined by the position of the selected reversing switch. If the reversing switch is closed with contacts 28, the motor will operate to drive the tuning control shaft 6 in= a counter-clockwise direction, since the reversing and control circuit for the motor is then closed through lead 16, and if the reversing switch is closed with contact 29, the motor will operate to drive the tuning control shaft 6 in y the opposite or clockwise direction.

In operating the selector means yof the present example the .switch arm 44 is turned to a contact 40 to connect one of the reversing and stop switches 30 to 37 inclusive, in the motor reversing circuit. The switch arm 44 is then pressed inwardly to close the contacts 45 and 46 to energize the motor and these contacts are held closed until the motor has operated to move shaft 6 and the tuning control device 5 such a. distance and in such direction as to bring said device exactly and automatically to a position preselected or predetermined by adjustment of an operating means 52 connected to move with the tuning control shaft 6 and associated with the reversing switches 30-37 inclusive and forming with the latter an adjustable selector mechanism.

Referring now to Fig. 2 along with Fig. l, the

operating means 52 includes a plurality of rotary cam members 53, one foreach reversing switch,

mounted on a common shaft 54 which is con-v spaced relation to each other along the shaft 54,

being each rotatably adjustable thereon, and are locked in place by suitable means, such as lock nuts 55, threaded onto the shaft.

Each of the cams is arranged to operate one of the reversing switches, which in the present example are provided with suitable cam followers 56 for engaging the cam surfaces, the cam followers being connected with a movable element of each switch such as the movable contacts or contact arms. The cams in the present example are of insulating material to insulate the switch arms and cam followers from the shaft 54 but any other suitable insulatingarrangement may be provided. For example the cam followers 56 may be of insulating material.

The cam surfaces with which the cam followers engage are annular in form, providing two slightly different levels 57 and 58 joined by an abrupt cam surface 59 of short length, the arrangement being such that the cam follower -causes the switch to move to the neutraL'open position when in contact with cam surface 59 and to move immediately to the closed position in one direction or the other when the cam moves the slightest ldegree in either direction therefrom by contactlng with one surface level 57 or the other 58 adjacent to the cam surface 59.

Each of the surfaces 57 and 58 is of the same level throughout with respect to the cam followers, whereby the reversing switches remain closed in one direction or the other when the cams are other than in the neutral position, and the surfaces are of equal length, extending in the present example through substantially 180 degrees for operation in direct connection with the control means 5 having the same degree of movement, thereby permitting full range of movement of each cam with the control means in either direction from a neutral position.

Although any suitable cam and reversing switch arrangement may be employed, in the present example and as a preferred arrangement for simplicity in construction and operation, the cam members are simple circular disks with simple annular cam surfaces of differing radii, provided on the peripheries thereof.

The reversing switches are simple spring levers or arms mounted at one end and provided with terminals for leads 39, on a strip 60 of insulating material, and extending at the opposite ends between contacts 28 and 29 which are adjusted to provideonly sufficient clearance to permit` each switch to open fully before engaging one or the other of said contacts.

The switch levers or arms lie tangentially with respect to each cam member provided for operating it and are provided with cam followers struck up integrally therewith, as indicated, of such length that under spring tension of the arm upwardly, the follower rmly engages the cam surface and may follow the throw of the cam in either direction and hold the switch exactly in the neutral or open position when engaging the cam surface 59. 'Ihe enlarged, detailed view in Fig. 2 of'one cam member and switch 33 illustrates the relation of the cam follower. switch and cam surfaces more clearly.

For convenient reference, the direction of rotation of the cams is indicated in Fig. 2 by the dotted arrows which have numerals corresponding to direction of operation corresponding to each of the switch contacts. The same arrow designation is made in connection with the switch 33 in Fig. 1. From this it will be seen that the short abrupt cam surface 59 provides a reversing ,point between two smooth operating sections 57 toward the cam follower and thereby to move the switch to the neutral or open position. Overtravel, as will be seen, is ,checked by the switch closing in a reversing position, and the load of the high ratio gearing and tuning control means prevents hunting.

'I'he direction and amount of travel of any cam and the tuning control `shaft and control member are determined by the angular or peripheral distance, in the present example of the reversing point on the cam from the cam follower, and the direction of rotation is always toward the reversing point. 'Ihe reversing point-:preferably may thus be utilized as the point of re'st or as the tuning adjustment point, for stopping the shaft of the means or control-shaft of the apdegree of accuracy in the adjustment of the selector tuning positions is readily accomplished by the above described selector mechanism by causing the change of level provided by the cam surface 59 of each cam to be abrupt and as short as possible consistent with smooth operation of the cam follower as the cam rotates. and by causing the throw of each switch between contacts and the throw of the cam between levels to be as short as possible, consistent with fully opening the electrical circuit when the switch is midway between its reversing contacts, substantially as indicated in Fig. 2, and further by utilizing the definite reversing point thus established, as the point of rest or tuning point for the control member oi' the apparatus.

It will Abe seen that the tuning control or control member 5 of the apparatus is automatically placed under control of any one of the plurality of control members or cams 53 by completing the reversing circuit of the motor through the reversing switch associated with said one of, the cams, and energizing the motor all by operation of the selector switch 38 at the remote control panel or station 43 as hereinbefore described.

The operation is as follows:

With the power circuit energized by closing switch 49, a cam 53 for operating one of the switches such as switch 33 is loosened on shaft 54 by loosening the locking nut 55 for that cam. 'I'he tuning control 5 is then adjusted by turning shaft 9 of the motor either manually or by operating the motor. In case the motor is utilized, the cam is rotated to close the reversing switch 33 in a direction to causethe motor to bring the-tuning control means to the desired position when the remote control selector switch 38 is operated. This switch is operated by moving it to close the motor reversing and control circuit with the selector contact 40 corresponding to the selector switch 33, as indicated in the drawings. and the motor is tnen operated by closing contacts 45 and 46 as hereinbefore described.

When the tuning control means 5 is adjusted to a desired position, such as a position corre spending to a desired signal channel or station to be received regularly under automatic control, the motor is stopped by opening contacts 45 and 46, and the cam isbrought to a pomtion as indicated in Fig. 2 to hold the reversing switch in its mid-position exactly. '-I'he locknut for that camisthentightenedtosecurethecamtothe shaft. The'other cams are then adjusted in the same manner for other desired settings of the timing control means corresponding to other preselected signal channels or stations.

Two of the cams, such as the c ams for operating switches 30 and 31, for example, may be adjusted as limit-control means by adjusting -them in such a manner that the switches are moved to the open or mid-positions at a point when the timing control means 5 isvln its minimum and its maximum tuning positions or at the extreme ends ol' its tuning range. Since these points are Y in the present example substantially 180 apart.

the cam surfaces 59 for operating switches 30 and 31 will be placed substantially as indicated in the drawings 180`apart. 'I'he adjustment is made in the same manner as for setting the selector mechanism for a. preselected signal channel or station wise direction until surface 59 opens switch 30 when the motor will'stop with the tuning control means 5 in its maximum position. Likewise when the motor reversing and control circuit is closed through switch 31 it will-be seen Vthat the tuning control means 5 will operate in counterclockwise direction until the cam surface 59 opens switch 3l and stops the motor with the timing control means 5 in its minimum tuning position.

By closing the selector contacts of the selector switching means 38 with any one of the other reversing and control switches, it will be seen that the tuning control means 5 will be moved exactly to the preselected positions as established by the positions of the cams on shaft 54. The setting of any or all of the cams may be changed from time to time to set up a diiferent group of preselected adjustments.

It will be seen that the selector mechanism determines the direction of operation and exact point of stopping of the motor and the controlled member or tuning control shaft 6 of the apparatus, for each selector contact in the selector switching means 38, whereby automatically the controlled member 6 may be moved exactly to predetermined or preselected positions corresponding to preselected channels or stations from any position of rest or motion. lConsidered in a broader aspect, this type of control operates to control at a distance a condition of operation of the apparatus and permits the condition of operation to be varied between exact and predetermined values.

In the control system oi the present invention,

the exact and precise setting or adjustment for each preselected position of the controlled member, which is extremeLv\import`ant in connection with the tuning control nieans of a radio receiver, is not attained by the addition of relays and complicated controls, but primarily by asimplitication ofthe control means and circuits, and by a simple and direct connection of the circuit control elements with the controlled member. or the tuning control shaft 6 in the present example. Such simpliiication for the exact and precise control of a movable member may be considered to begin with the choice of the motor means, which as described, is of a type having a simpliiled control and reversing circuit provided with only a common return and two reversing leads;A

This type of motor has the advantage that the control circuit isadapted not only for reversing but also for starting and stopping under control of a simple single-pole double-throw switch or its equivalent. 'l'he remote 'control feature ofthe circuit then involves only the extension of the return lead of the control and reversing circuit to a remote point through a control switch provided with a suitable number of selector points, one for each reversing switch or channel desired.

T'he number of selected channels or positions of the tuning control means of the controlled element of the apparatus which may be provided for automatic selection and control is not necessarily limited tothe number shown in the present example and may be more or less as is desited, although the six channels provided. together with the limit controls. are the usual number which will be found useful without causing the control system to require a remote cable connection of large size or a selector mechanism in the apparatus of too great length. A Referring now, along with Fig. 1. to Fig. 3 in which the same reference numerals have been usedlorlikepartsasintheprecedingngures:

a power switching means is shown in connection with the tuning control shaft 6 for automatically opening and closing the power circuit directly in the apparatus and under remote control without extending the power switching leads 20 through the cable 42 and to the remote control panel 43 and without employing relays. This is for the purpose of eliminating the alternating current power supply leads from the cable, thereby reducing the size of the cable and the number of leads therein and further simplifying the control.

A power switch 61 is connected with leads 20 for the power supply circuit and is placed as indicated in a position to be operated by rotation of the tuning control shaft 6 of the apparatus. For this purpose the power switch 61 is of the same type as reversing switches 30-3'1 inclusive, being of the spring arm type adapted to be operated by a cam 62 mounted upon an extension 63 of the control shaft 6. The cam is provided with a surface 64 for maintaining the power switch 61 -in a closed position while the tuning control shaft 6 rotates through its operating range and with a surface 65 which permits the switch to open when the control shaft 6 is moved to a position in which the tuning control means 5 is at one or the other of the extremes of its tuning control range., In the present example, the cam surface 65 is adjusted to a potion such that it opens the power switch 6l when the tuning control means 5 is in its minimum tuning position.

With the above described control arrangement for the power circuit, it will be kvseen that the apparatus may be deenergized by closing the remote selector switch through reversing switch 3l whereupon the tuning control means will be moved automatically to the minimum position and the power supply switch 6l will be thereby automatically opened. In a control system of this character the switch 61 controls only the current supply to the transformer 26 the motor supply transformer 19 being continually energized from the supply circuit 18 whereby the motor may be operated and the apparatus or set may be energized through transformer 26 by operating the remote selector switch 38 to any one of other positions.

f Referring now to Fig. 4, along with Fig. 1, a modification of the remote control unit 43 is shown at 66. This is connected with' the terminals of terminal board 25 through the same cable terminals 24, 23, 51' and 27 as in Fig. 1 and for the same purpose. In this modification of the remote selector unit, the unitary control arrangement provided by' selector switch 38 is divided among a series of push-button switches 67-74 inclusive, one for each preselected channel for automatic operation of the remotely controlled apparatus. In the present example, eight switches are provided, one for each of the reversing switches in the selector mechanism and in each of said switches are provided the same control contacts as provided in switch 38. These include contacts 45 and 46 in each switch, connected respectively with leads 22 and 21, for energizing the motor when closed, and contacts 40 connected with their respective reversing switches through the leads 39 as shown and described in connection with Fig. l. Each of the switches 67-74 inclusive is closed by closing all three contacts together. As will be seen, this operation serves to close the motor energizing circuit by connecting together the leads 22 and 21 and completes the motor reversing and con-l trol circuit through lead 22, contacts 40 and 45. and a selected one of the reversing'switches 30-3'1 inclusive.

It will be appreciated that the above switching arrangement carries out the same switching control and for the same purpose as the switching means 38 oi Fig. 1. The switch for the selected channel is held closed until the motor has moved the remotely controlled shaft of the tuning means to the preselected position wheny it is released. The volume control device 50 for the apparatus is provided on the control unit and is connected with terminals 51 through cable leads 51.

The control unit of the present example is adapted for use with a power switching means such as that shown in Fig. 3, and accordingly a power switch is not provided in connection with the remote control unit. Terminals 27 for the power switch are therefore not utilized.

It will be appreciated that a remote control unit such as that shown in Fig. 4 having individual selector switches may be operated other than by manually operating the switches 67-74 inclusive. For example, these switches may be operated in a clock mechanism such as that indicated at 75, the switches being arranged to be operated by the clock mechanism at predetermined hours whereby the apparatus may be automatically set for predetermined conditions of operation or be tuned to preselected channels at predetermined hours or for predetermined time intervals. The clock vmechanism may be arranged in any suitable manner to close the various switches in proper sequence.

, With the above described arrangement, the apparatus may also be turned oil or deenergized by operating the switch 67 by lmeans of the clock mechanism at a designated hour and likewise, the apparatus may be energized by operating the switch 68 or any of the other switches 69 to '74 inclusive in a similar manner at other designated hours.

In the present example the switches 67-74 inelusive are maintained in the remote control unit 66 for manual control and a similar set of switches are provided in the clock m, connection for such switches in parallel with those shown being made through a suitable cable connection having leads 'I7 connecting with the various control leads for switches 67-74 inclusive whereby the corresponding switches in the clock mechanism are connected in parallel with said switches. In the clock mechanism suitable time selector dials 78 are provided for each of the individual switches whereby the time of operation of the individual switches may be adJusted. As the internal mechanism of the clock does not concern the present invention, the same is not illustrated, it being suflicient that any suitable mechanism beprovided to operate switches similar to switches 67-'14 under time control instead of manually. This circuit arrangement is therefore readily adapted for control by any suitable time control mechanism provided with switching means such as the switching means shown in the remote control unit 66. y

WhatIclaimasnewand desiretosecureby Letters Patent oi' the United States, is:

1. A remote control system for a radio apparatus having a. control shaft, a current source, a reversible electric motor to drivesaid shaft having energizing windings and two sets of control windings. a reversing switch for the motcr having positions for operating the motor in a forward and a reverse direction and a neutral position for stopping the motor, a remote control switch in circuit with said reversing switch and the motor for connecting said energizing windings to said source and simultaneously for controlling the motor when said reversing switch is in an operating position, and operating means for the reversing switch providing a connection with the shaft whereby said reversing switch is moved to the neutral position in response to movement of said shaft, one ofI said sets of control windings being short-circuited through said reversing switch and said remote control switch when said reversing switch is in the first-named position and the other of said sets of control windings being short-circuited through said reversing switch and said remote control switch when said reversing switch is in the second-named position.

2. A remote control system for a radio apparatus having a control shaft, a reversible electric motor to drive said shaft having energizing windings and having two sets of control windings, a reversing switch for the motor having positions for operating the motor in a forward and a reverse direction and a neutral position for stopping the motor, a current source, a pair of leads adapted to conduct current from said source to said energizing windings, a remote control switch for connecting said source to said energizing windings through said leads and simultaneously for controlling said motor when said reversing switch is in an operating position, and operating means fr the reversing switch providing a connection with the shaft whereby said reversing switch is moved to the neutral position in response to movement of said shaft, one of said sets of control windings being short-circuited through said reversing and control switches and one of said leads when said reversing switch is in the first-named position, and the other of said sets `of control windings being short-circuited through said reversing and remote control switches and said one of said leads when said reversing switch is in the second-named position.

3. A remote control system for a radio apparatus having a control shaft. a current source. a reversible electric motor to drive saidshaft havingwindingsandhavingtwosetsof control windings, a reversing switch for the motor having for operating the motor inaforwardandareversedirectlqiandanmtralposition forstoppingtbemotomarenote control switchin circuitwlthsaidswltch and the motor for said windings to said soprce and foml controlling the motor when said switch isinanoperatingpositiomandoperatingmeans for the reversing switch including a cam connectedto theshafttorotatetherewithwhereby said reversing switch is moved to the neutral position in response to movement of said shaft. one of said sets of control windings being shortcircuited through said reversing switch and said remote control switch when said switch is in the mst-named position, and the other of said sets of control windings being short-circuited through said reversing switch and said remote control switch when said reversing switch is in the second-named position.

4. A remote control system for a radio apparatus having a control shaft, a reversible electric motor to drive said shaft having energizing windings and having two sets of control windings, a plurality oi' reversing switches for the motor each having positions for operating the motor in a forward and a reverse direction and a neutral position for stOpping the motor, a current source, a pair of leads adapted to conduct current from said source to said energizing windings, a remote control switch for connecting said source to said tion.

- CHARLB R. GARRETI. 

